Include the instructions for the problem. Don't assume that there is only one obvious thing to do with an expression.
Put multiple-term numerators and denominators in parentheses. What you posted meant:
But I'm pretty sure you intended:
Assuming that the expression is:
and the instructions are "Rationalize the denominator" (or something to that effect), then we will take advantage of the factoring pattern:
This pattern shows how a two-term expression times a certain three-term expression results in an expression of perfect cubes. The denominator we have to rationalize is a two-term expression which matches the pattern of (a+b). So the pattern shows how to turn that into an expression of perfect cubes. Since the cube of a cube root is rational, this is our path to a solution. In our denominator, the "a" is and the "b" is . If we multiply the numerator and denominator by the corresponding we will reach our goal:
In the denominator the pattern tells us how it works out:
which simplifies to:
then
(